Entire heating running from 15mm

12 Apr 2009
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United Kingdom
I’m planning to increase the size of my radiators downstairs. They currently pump out about 3-4K btu in the dining/kitchen and living room but the online calculators seems to recommend about 7k.

In the picture below you can see the 22mm flow and return pipes coming from the boiler, the first tee goes to the bathroom radiator, the reducer down to 15mm seems to provide heating to every other radiator in the house,’ which is probably something around 18-20k btu.

I’m thinking this is too much for the 15mm pipe and am thinking about extending the 22mm pipe in the ceiling and running another 15mm tee off that to provide heat to two 3.5k btu radiators in the dining/kitchen and one 7k btu radiator in the living room. The rest of the system will tee off this 22mm pipe meaning about 13k btu will go through this 15mm pipe for the rest of the system.

I suppose I just want to confirm this all makes sense? I’m running a 24kw combi boiler.

On another matter it doesn’t seem practical for me to be able to switch to ASHP at any point - it would seem like I wouldn’t have room for the larger radiators required.


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